As an electric power converter that performs power conversion between DC power and AC power, one that has a laminated body obtained by laminating a plurality of semiconductor modules with built-in semiconductor elements and a plurality of cooling pipes for cooling the semiconductor module, and that houses the laminated body in a metal casing has been known (refer to Japanese Patent Application Laid-Open Publication No. 2013-55840).
In the abovementioned electric power converter, a pressing member such as a leaf spring is housed in the metal casing. The laminated body is pressurized in a laminating direction by the pressing member. Thereby, it is configured that while ensuring a contact pressure between the semiconductor modules and the cooling pipes, the laminated body is fixed in the metal casing. Moreover, a capacitor connected to the semiconductor modules is housed in the metal casing.
The metal casing includes outer wall portions that form an outer shell, and partition wall portions formed in the case, which are connected to the outer wall portions. A space within the metal casing is partitioned into a capacitor housing space for housing the capacitor and a laminated body housing space for housing the laminated to body by the partition walls. The pressing force of the pressing member is applied to the partition walls.
The capacitor includes a capacitor case made of resin, capacitor elements disposed in the capacitor case, and a sealing member for sealing the capacitor elements in the capacitor case. The capacitor is housed in the capacitor housing space. A gap is formed between the capacitor case and the metal casing (refer to FIG. 10).
However, the above-mentioned electric power converter has a problem that cooling performance of the capacitor is not sufficiently high. That is, as described above, in the above-mentioned electric power converter, the capacitor elements are sealed in the capacitor case, and the gap is formed between the capacitor case and the metal casing. Thereby, the heat generated from the capacitor elements is transmitted to the metal casing via the sealing member, the capacitor case, and the gap. Therefore, a thermal resistance from the capacitor elements to the metal casing is large, and it is impossible to increase sufficiently the cooling performance of the capacitor.
Further, since there is the gap between the partition wall and the capacitor in the electric power converter, it is necessary to receive the pressing force of the pressing member on the partition wall. Therefore, in order not to cause it to deform due to the pressing force, it is necessary to form the partition wall thickly. Thus, there is a problem that it is difficult to lighten the electric power converter. Further, when the partition wall is thick, it becomes difficult to reduce the size of the metal casing, which makes it difficult to downsize the electric power converter.